| dc.description.abstract | In recent years, the earthquake caused many disasters in Taiwan, so seismic design specification to improve the design seismic forces. Therefore the spread foundation wide obviously is too large in some reinforcement and new cases. The main reason is improving the design seismic forces. And the foundation of pressured area have to satisfy the specification, therefore the size of foundation must be expanded. Based on the past experience, the rocking mechanism of spread foundation can reduce the seismic force of the main structure, besides it can extend the period of structure and decrease the seismic force. In addition, the soil will generate the plastic behavior and absorb the seismic energy under the extreme earthquake.
In the past, the research subjects was single pier of spread foundation. There was not the research about the rocking mechanism of simply supported bridge. Therefore, the research of simply supported bridge is main subject. First, I build a numerical model in the commercial software SAP2000 and proceed the dynamic analysis. Next, we advance a series of shaking table tests to verify feasibility of spread foundation with linear numerical model. And then, we observe the deck quality, column height, the pier foundation area, the effect of soil strength to rocking.
In the experiment, we can know that the stain of column base will be greater with heavy deck and high column height. On the other hand, the smaller footing size and lower rubber stiffness are facilitate to rocking effect. It can reduce the stain of column base and extend the nature period of the structure for isolation effect. When it is rocking, the nature frequency of the structure system will be close to major earthquake vibration frequency.
| en_US |